This invention relates to vinylidene chloride polymer (PVDC) compositions having improved extrudability.
To control the generation of PVDC degradation products during melt processing, processing aids such as lubricants (e.g., internal and external types), olefinic waxes and oils have been blended with the vinylidene chloride polymer prior to fabrication into a final product. However, it has been found that, after prolonged periods of extrusion under desirable processing conditions, an excessive degree of adhesion develops between the vinylidene chloride polymer and the metal surfaces of the extruder screw and die. This adhesion increases the residence time of the vinylidene chloride polymer which promotes degradation, resulting in the formation of die face build up or die slough generation, and in the generation of carbon buildup on the screw and die metal surfaces
It would be desirable to provide a vinylidene chloride polymer composition which is capable of being extruded, in either powder or pellet form, without having an unacceptable level of degradation which results from excessive adhesion between the PVDC melt and the screw and die metal surfaces.